1. Field
Embodiments discussed herein relate to an apparatus and method to track positions of multiple sound sources, which can simultaneously track positions of multiple sound sources.
2. Description of the Related Art
Technologies to track the position of a sound source are used not only for electronic appliances but also for devices such as a service robot that supports household affairs, a surveillance camera that tracks a sound source to monitor intruders, and a video camera used for multipoint video conferencing.
Great efforts have been made on research and development of an apparatus and method to track the position of a sound source by analyzing signals input to a microphone array including a number of microphones arranged in series or parallel.
In one method that can be considered, the respective input signals of the microphones are compensated according to sound wave arrival time differences due to the differences between the lengths of sound wave propagation paths from the position of the sound source to the microphones and an angle at which the power of the sum of the compensated signals is maximized is found to determine the position of the sound source.
However, it is difficult to apply the conventional sound source position tracking to actual environments since it is designed to track one sound source or to track one sound source having a relatively high sound pressure level among multiple sound sources. For example, a technology to simultaneously track a plurality of sound sources is needed to allow a service robot to clearly identify a voice of the owner and to correctly execute commands thereof in environments in which a variety of household noise such as TV noise, vacuum cleaner noise, washing machine noise, doorbells, conversation between family members, and outdoor noise are present.
To track the positions of target sound sources such as a speaker's voice in real time and to correctly execute user commands in an environment in which a variety of noise is present, it is necessary to separate signals received from a microphone array into sound source signals and to determine the positions of the sound sources based on the sound source signals.
The conventional sound source position tracking requires a large amount of calculation when tracking sound sources since it requires a process to detect sound source signals in all directions, a time-to-frequency conversion process, and a frequency-to-time conversion process.